Audit pass with the threats that actually apply to a self-hosted, account-less
app: getting the Ollama key throttled or banned, and someone grinding the app
down. Per-route windows already existed; these are the missing layers.
- lib/model-guard.ts: every route that spends a model call now takes a slot —
60 calls per window across all clients (RATE_LIMIT_MODEL_TOTAL), 3 in flight
per IP, 6 in total — and the slot is released when the call finishes, on
errors and on client disconnects. Over the concurrency cap answers 429
kind=busy, not a punishment. Slots are taken after every cheap rejection so
a malformed request cannot hold one (found by the new suite: early 400s
were leaking slots).
- Images must be base64 data URLs (dataUrlSchema in lib/schemas): a plain URL
in an images field made Ollama fetch an arbitrary address on our behalf.
- Push endpoints must be a real push service (PUSH_ALLOWED_HOSTS, defaulting
to FCM/Mozilla/Apple/WNS): the server POSTs to whatever is stored.
- The rate-limit identity is the LAST x-forwarded-for hop. Reading the first
let a client spoof its own IP and dodge every per-IP limit.
- Disk guards: reports.jsonl stops at REPORTS_MAX_BYTES (8 MB), reminder
devices cap at PUSH_MAX_SUBSCRIPTIONS (50).
- Security headers: frame-ancestors 'none' + X-Frame-Options DENY, nosniff, a
referrer policy and a Permissions-Policy without camera/mic/geo/payment.
New tests/security-test.mjs (13 checks, registered in run-all) proves each
guard against a slow stub Ollama with deliberately tiny limits. README:
security notes + rate-limit tables updated. Version 0.1.3, SW -> v51.
Martin Dvorak
8822baf4b7